Nonaqueous electrolyte battery attracts attentions as power sources used for hybrid vehicles, electric vehicles, and a like. Such a use requires that the nonaqueous electrolyte battery have such performances as a large capacity, long life, and good input/output performances.
Generally, a carbon based material has been used as a negative electrode active material for a nonaqueous electrolyte battery. Recently, lithium titanate having a spinel structure has also been used. The volume of Lithium titanate having a spinel structure is not changed with a charge/discharge reaction. Therefore, it has an excellent cycle performance. Further, it has high safety because Lithium titanate having a spinel structure has a low possibility of occurrence of lithium dendrite compared with the case of using a carbon based material. Further, because the lithium titanate is ceramics, thermo runaway of the battery is hard to occur.
On the other hand, a monoclinic β-type titanium complex oxide has attracted remarkable attention as a negative electrode active material in recent years. The monoclinic β-type titanium complex oxide has the advantage that it has a high capacity.
In nonaqueous electrolyte battery using a material like that mentioned above, it is desired to more improve performances such as a large capacity and long life.